The objectives of the studies proposed herein are to develop techniques for the study of phosphoryl transfer mechanisms and to apply these techniques along with existing ones to detailed characterization of the catalytic mechanisms of selected enzymes which catalyze intra- and inter-molecular phosphoryl transfer reactions. The techniques that we wish to explore will involve, (i) the preparation of new M(III) complexes of ATP, ADP and PP to be used to probe enzyme substrate specificity and chemical mechanism, and (ii) the preparation and stereochemical assignment of the diastereomers of Beta, Gamma-bidentate Cr(III)ATPGammaS and Alpha, Beta-bidentate Cr(III) - ADPBetaS to be used as probes of the active sites of ATP-dependent enzymes. The enzymes which will be subjected to detailed study include yeast inorganic pyrophosphatase which catalyzes the hydrolysis of inorganic pyrophosphate and Tetrahymena pyriformis phosphoenolpyruvate phosphomutase which catalyzes the rearrangement of phosphoenolpyruvate to pyruvate phosphonic acid.